1. Field of the Invention
This invention relates to a display system for a conventional high-range-resolution monopulse radar and especially to a display system which utilizes four dimensions of target data, namely, azimuth, elevation, range and range video to form an isometric image of the target on an x-y display.
2. Description of the Prior Art
Tracking radars are used principally for continuously measuring the position of a target in range, azimuth angle and elevation angle. These radars typically employ an antenna which radiates a pencil-beam from a rotating platform which is controlled in azimuth and elevation position by angular error signals which cause the antenna to change position keeping the target centered in the beam. These radars also typically employ a display which shows the target as a point source of brightness on a CRT usually indicating the range, range and azimuth, or range, azimuth and elevation of the target, depending on the type of display.
High-range-resolution monopulse radars such as described in U.S. Pat. No. 3,747,097 resolve the return signal from each reflecting surface of a target thus allowing the radar to obtain azimuth, elevation, range and range video information for each reflecting surface. Range video information is the radar echo amplitude of the signal returned from each reflecting surface which indicates its cross-sectional area.
Resolution of each part of a target provides information for a complete target image to be presented on either an x-y display or a three-dimensional display. U.S. Pat. No. 3,747,097 describes a visual display system which presents a target image on an x-y display. This x-y target image displays three dimensions of data, either range, azimuth and range video information or range, elevation and range video information. However, such a system cannot display both elevation and azimuth information simultaneously.
To overcome this, three-dimensional display presentations such as that shown in U.S. Pat. No. 3,887,917 and 3,555,349 were developed. These three-dimensional displays require a series of planar display windows in a stacked fashion which allow four dimensions of data to appear in three dimensions. These displays are structurally complicated and expensive.
U.S. Pat. No. 3,792,423 describes an isometric imaging system for obtaining the projection of four dimensions of data onto an x-y display. The technique described has several drawbacks in that all x and y values to the display must undergo a trigonometric transformation and the isometric image is constructed slowly on the display by a scanning technique.